Peristaltic pumps are utilized in a variety of applications to feed fluids along a length of compliant or flexible tubing. Peristaltic pumps provide non-contact fluid flow, allowing the use of disposable tubing while maintaining the integrity of the fluid path. Peristaltic pumps are particularly useful in pumping arrangements for corrosive materials or hygienic materials because the pumped material does not come into contact with the mechanical structures defining other parts of the pump.
Peristaltic pumps include compression units, generally in the form of rollers, that compress the tubing against a raceway. Successive rollers capture a “pillow” of fluid within the tubing, pushing the pillow forward as the rollers progress along the tubing.
A variety of arrangements has been utilized for mounting the rollers. For example, some pumps include fixedly mounted rollers, while others include rollers that are outwardly biased, either as a unit, as for example in U.S. Pat. No. 5,110,270 to Morrick, or individually. Those rollers that are individually outwardly biased, may be on pivoting shafts that are sprung individually, as in U.S. Pat. No. 3,644,068 to Lepak, or by way of lever arms, as in as in U.S. Pat. No. 2,314,281 to Knott. Alternately, they may include individually outwardly biased shafts disposed in channels, as in U.S. Pat. No. 4,278,085 to Shim. Pumps with compliant or sprung rollers more easily accommodate various tubing sizes and tubing tolerances. Additionally, compliant rollers can reduce audio output from the pump heads. A common feature of many of the available designs is that, as a result of exposed mechanical elements such as the biasing features, the pumps can be difficult to clean when fluids reach areas outside of the tubing. Further, many present complex designs may be difficult to repair or may limit the number of rollers that may be utilized without a restructuring or redesign of the arrangement.